DeepSeek ships V4.1-Flash-1017 update with MIT weights and higher agent and coding scores

What DeepSeek released

DeepSeek released DeepSeek-V4.1-Flash-1017 on 17 October 2026. The release note says the model is live on the website, app and API, with open weights on Hugging Face and ModelScope. The model card calls it a minor update to DeepSeek-V4.1-Flash, which shipped on 10 September, and states that the repository and weights are licensed under MIT.

Hugging Face lists the checkpoint at 763B parameters. The V4.1-Flash card describes a 552B-parameter backbone with 8B parameters active during prefill and 16B during decode, plus image input through a DeepSeek-ViT encoder. The active parameter count for the 1017 update is not listed separately. The card recommends a 1M-token context, max_tokens of at least 256K, and temperature and top_p of 1.0.

What changed in the update

DeepSeek says the update was trained with reinforcement learning with self-feedback to improve end-to-end project development, from game creation to 3D modeling. It is tuned for DeepSeek Harness, Tencent CodeBuddy and WorkBuddy, and DeepSeek recommends DeepSeek Harness v0.2.1-rc.1 or later. On the card, the new model scores 42.6 on Humanity's Last Exam without tools against 36.8 for V4.1-Flash, 42.3 on Terminal-Bench 4.0 against 31.2, 29.1 on ProgramBench against 20.3, 72.1 on Apex Bench v1.1 against 64.6 and 92.5 on BabyVision with tools against 89.6.

DeepSeek also says the model finishes tasks faster and writes shorter outputs, and calls the result a Pareto improvement in performance and cost. The output-length and cost-per-task figures appear only in charts, so the exact numbers are not stated in the announcement text.

What changed for API users

The pricing page maps deepseek-flash to the 1017 model, with a 1M-token context and 384K maximum output. On 28 October it listed $0.003 off-peak or $0.006 peak per 1M cache-hit input tokens, $0.15 or $0.30 per 1M cache-miss input tokens, and $0.60 or $1.20 per 1M output tokens. Peak hours are 01:00 to 04:00 and 06:00 to 10:00 UTC on weekdays. Requests to the retired deepseek-v4-flash and deepseek-v4-flash-vision-exp names are served by the 1017 model at the Flash price. The same note opened Search and Fetch APIs at $0.75 per 1,000 calls per endpoint, with server-side calls from DeepSeek Harness, Claude Code and Codex free until billing starts on 31 October 2026 at 16:00 UTC.

What to watch next

DeepSeek does not say whether DeepSeek-V4-Pro, still served as deepseek-v4-pro from its August build, will get a similar update. Independent runs will test the vendor scores; Reflection AI's Beam announcement already lists V4.1-Flash at 90.6 on Terminal Bench v2.1. The release is on the AI model release tracker, and more open-weight news is under Open Source AI.

Questions people ask

Is DeepSeek-V4.1-Flash-1017 open source?

DeepSeek publishes the weights on Hugging Face and ModelScope, and the model card states the MIT license for the repository and weights.

How much does deepseek-flash cost?

DeepSeek's pricing page lists $0.30 per 1M cache-miss input tokens and $1.20 per 1M output tokens at peak, with off-peak rates at half those prices. Cache hits cost $0.006 per 1M tokens at peak.

What changed from DeepSeek-V4.1-Flash?

DeepSeek says the update scores higher on reasoning, coding, agentic and visual benchmarks, for example 42.3 against 31.2 on Terminal-Bench 4.0, and finishes tasks faster with shorter outputs.

Sources

1. DeepSeek-V4.1-Flash-1017: Wish-Driven Programming Made Real (DeepSeek, 17 Oct 2026)
2. DeepSeek-V4.1-Flash-1017 model card (DeepSeek on Hugging Face, 17 Oct 2026)
3. Models and pricing (DeepSeek API Docs, 28 Oct 2026)
4. DeepSeek-V4.1-Flash model card (DeepSeek on Hugging Face, 10 Sep 2026)